What is the 'easiest' modern engine to swap in.

[TR]

There is great SR support for 510's (1600's) in Australia:

http://www.datsport.com/menu.html

http://www.maddat.com.au/engine-fitting-kits.php

I'm sure either of those outfits could help you with parts, this site has plenty of info on how to complete the swap...

May not be the easiest or best swap, but there is something nice about having it still be Nissan made...

Good luck with whatever you decide and enjoy it! TR